The minimal JavaScript to select an EIP-6963 wallet as window.ethereum in the DevTools console for quick testing.

eip-6963.js

// EIP-6963: Multi Injected Provider Discovery
// https://eips.ethereum.org/EIPS/eip-6963

const wallets = [];
window.addEventListener('eip6963:announceProvider', e => wallets.push(e.detail));
window.dispatchEvent(new Event('eip6963:requestProvider'));

console.table(wallets.map(w => w.info.name));
console.log('Wallets have been collected in the \x1B[1;4mwallets\x1B[m object.');
console.log('Basic example to set window.ethereum:\n    \x1B[1mwindow.ethereum = wallets[0].provider;\x1B[m');
console.log(`If you are using Rainbow, it's not possible to directly overwrite window.ethereum. Instead, you must use the new properties defined by Rainbow:\x1B[1m
    window.rnbwWalletRouter.currentProvider = wallets[0].provider; // Will set window.ethereum to wallets[0].provider\x1B[m`);

// More info on Rainbow's new properties:
// https://github.com/rainbow-me/rainbow/blob/f8e1815c40a692b32a4450cedab812e5ee18f450/src/browser/inpage.ts#L89